Chemical composition and hydrocarbon fuel containing same



United States Patent 3,259,477 CHEMICAL COMPOSITION AND HYDROCARBON FUELCONTAINING SAME John H. Udelhofen, Calumet City, 111., assignor toStandard Oil Company, Chicago, 111., a corporation of Indiana N0Drawing. Original application Apr. 28, 1961, Ser. No. 106,198, nowPatent No. 3,150,147, dated Sept. 22, 1964. Divided and this applicationMay 22, 1963, Ser. No. 287,457

4 Claims. (Cl. 44-63) This is a division of application -S.N. 106,198,filed April 28, 1961, now US. Patent No. 3,150,147.

This invention relates to chemical composition useful as a corrosioninhibitor in hydrocarbon fuels. This invention further relates tohydrocarbon fuel compositions containing new and useful corrosioninhibitors.

The chemical compositions of this invention are salts of1,2-disubstituted imidazol-ine and citrimic acid. The salts may berepresented by the structural formula:

i F i oo--ornoo n o RN\ H 0 01110 111-1? 1? fiF-C Hg CHzCHg o In theformula, R and R each represent an open-chain aliphatic hydrocarbonradical of 8 to 22 carbon atoms. The hydrocarbon radicals may be asaturated or unsaturated hydrocarbon, e.g., alkyl, radical having eithera straight or branched chain.

The salts may conveniently be prepared by reacting eq-ui-molar amountsof the corresponding 1,2-disubstituted imidazoline and N-substitutedcitrimic acid. The reaction proceeds readily at room temperature but thereactants may be heated and agitated if desired to increase the reactionrate. The react-ion is complete when heat of reaction ceases to beevolved. The reaction is a neutralization reaction with resulting saltformation; such reactions and their conditions, as well as useablecatalysts, are well known to the art.

The citrimic acid andv 1,2-disubstituted imidazoline used in the abovereaction may be purchased or may be prepared by methods known in theart. The 1,2-disubstituted imidazolines may be prepared by reaction ofthe corresponding carboxylic acid (RCOOH) with 'N-hydroxyethyl ethylenediamine until two moles of water are split out; this occurs upon closureof the imidazoline ring. The N-substituted citrimic acid may be preparedby reaction of equimolar amounts of a primary amine (RN-H with citricacid under known conditions to form the imido linkage with the resultingsplitting out of tWo moles of water.

Illustrative examples of N-substituted citrimic acid salts of1,2-disubstit-uted imidazolines are l-( 2-hydroxyethyl) Z-heptadecenylimidazolinium N- tallow citrimate,

1-(Z-hydroxyethyl)2-(2,4-dimethyl hexyl) imidazolinium 'N-eicosylcitrimate,

1-(2-hydroxyethyl) Z-palmityl imidazolinium N-caprylyl citrimate,

1-(2-hydroxyethyl) 2-la-uryl imidazolinium N-lauryl citrimate,

1-(2-hydroxyethyl) 2-n-octyl imidazolinium N-n-octyl citrimate,

1-(2-hydroxyethyl) Z-n-decenyl imidazolinium N-tallow citrimate,

1*(2-hydroxyethyl) 2-linolenyl imidazolinium N-stearyl citrimate,

3,250,477 Patented July 5, 1966 l-(Z-hydroxyethyl) 2-stearylimidazolinium N-octadecadienyl citrimate,

l-(Z-hydroxyethyl) 2-nonyl imidazolinium N-capryl citrimate,

l-(2-hydroxyethyl) 2-coco imidazolinium N-coco citrimate,

l-(Z-hydroxyethyl) 2-eicosyl imidazolinium N-eicosyl citrimate,

1-(2-hydroxyethyl) 2-myristyl imidazolinium N-oleyl citrimate,

l-(Z-hydroxyethyl) 2-docosyl imidazolinium N-docosyl citrimate,

1-(2-hydroxyethyl) 2-monohydroxystearyl imidazolinium N-decyl citrimate,

l-(2-hydroxyethyl) 2-linoleyl imidazolinium N-decyl citrimate,

1-(2-hydroxyethyl) 2-soybean imidazolinium N-tallow citrimate,

I-(Z-hydroxyethyl) 2-tallow imidazolinium N-tallow citrimate,

I-(Z-hydroxyethyl) 2-(3-ethyl hexyl) imidazolinium N-oxooctyl citrimate,a'nd 1-(2-hydroxyethyl) 2-tallow imidazolinium N-coco citrimate.

The terms coco, soybean and tallow as used herein designate that thedefined group was derived from coco fatty acids, soybean fatty acids andhydrogenated tallow fatty acids. Such fatty acids and the correspondingamines which are derived therefrom are well known to the art. Forexample, hydrogenated tallo-w acid predominates in stearic acid andcontains a substantial amount of palmitic acid and very small amounts ofmyristic oleic acids. Coco fatty acid (distilled) contains about 50%lauric acid and the remainder of the acids range from C to C including.caprylic, capric, rny-ristic, palmitic, s-tearic, oleic and linoleicacids. Soybean fatty acids include mixtures of saturated and unsaturatedacids in the C range.

The salts of this invention, as described above may be defined in a moreparticular aspect of this invention as the I-(Z-hydroxyethyl)2-aliphatic imidazolinium CN-aliphatic citrimates wherein the aliphaticgroups are the same or different open chain (non-cyclic) aliphaticcontaining from 8 to 22 carbon atoms. The aliphatic groups may besaturated or unsaturated but are preferably saturated, mono-unsaturatedor di-unsaturated.

As a typical preparation of salts of this invention, equimolar amountsof N-tallow citrimic acid and I-(Z-hydroxyethyl) Z-heptadecenylimidazoline were mixed in isopropyl alcohol solvent with stirring whileheating slightly above room temperature for about 30 minutes. Theisopropyl alcohol solvent was then evaporated from the resultingproduct. The product was 1-(2-hydroxyethyl) 2- heptadecenylimidazolinium N-tallow citrimate.

The above-defined salts are useful as corrosion inhibitors in minoramounts sufiicient to inhibit corrosion in hydrocarbon fuels. Moreadvantageously, the salts may be used in amounts of from about 0.00005to about 1.0 weight percent and preferably in amounts of from about0.0001 to about 0.0015 weight percent. Concentrates of the salts inhydrocarbon fuels or other suitable solvent, such as xylene, toluene,benzene, phenol, isopropyl alcohol, ethanol, n-butanol, etc., are alsointended. Such concentrates may contain the salt in an amount greaterthan normally used in hydrocarbon fuels as set out above, for example inan amount in the range of 10 to 70% by weight in a suitable solvent. Theprimary function of the R and R groups in the above formula is to impartoil-solubility to the chemical compounds for use in hydrocarbon fuels asadditives and the particular number of carbon atoms in the R and Rgroups is not critical. Other addition agents such as anti-knock agents,anti-ice agents, antioxidants, preignition suppressors, dyes, etc., mayalso 'be added to the hydrocarbon fuel composition or additiveconcentrate when desired. The salts of this invention, in addition tobeing effective corrosion inhibitors, are also effective rustinhibitors.

The corrosion inhibitor of this invention are effective in both thehydrocarbon and aqueous phases encountered in the handling and storageof fuels. Hydrocarbon phases are present as the fuel itself and theaqueous phases are produced by condensation and in some cases bycontamination through seepage or from processing of the fuel. Alsopresent in the fuel in many instances are acidic and/or causticsubstances in small amounts resulting from prior treatment of the fuelor a component thereof, e.g., from acid treating and/ or caustictreating. Such acidic and/or caustic materials are corrosive towardmetal parts such as storage tanks, valves, pipelines, tank cars,burners, etc. Other corrosive substances may be formed through oxidativedeterioration of the fuel in the presence of oxygen, particularly if thefuel is stored for substantial periods of time or stored or transportedunder adversely high tema 1A position (Preparations A through Q)prepared for comparison purposes were each subjected to the followingcorrosion test procedure:

Each sample was placed with an equal volume of an aqueous phase in atest tube and stirred briefly to permit the corrosion inhibiting agentto be distributed between the two phases. Stirring was thendiscontinued. An S- shaped steel test strip, having an electricalterminal at each end of the S was immersed in the oil phase to reachadsorption equilibrium and the electrical resistance was noted as acontrol resistance value. The steel test strip was then lowered into theaqueous phase and after 24 hours the change in electrical resistance wastaken as a measure of corrosion during the 24-hour period. The amount ofcorrosion was then compared with the amount of corrosion obtained in acontrol run without the inhibitor. Results are reported in the table interms of percent reduction in corrosion compared with the control run.One hundred percent reduction is equivalent to absence of measurablecorrosion. The aqueous phases used consisted of water containing theamounts of corrosive substances listed in the table below.

TABLE Addition Agent Percent Reduction in Corrosion Sample HydrocarbonFuel Electrolytes in Identity Concen- Aqueous Phase:

tration 0.1% 3.6)(10- NaCl HCl Preparations A and B N-tallow citrimicacid gggl': g" fggi if:":: Preparations o and D l-(z-hydroxyethyl)2-heptadecenyl imidazoline 1 Gasglmmfl Examples 1 and 21-(2-hydroxyethyl) 2-heptadecenyl imidazo- 99 96 linium N-tallowcitrimate. 99 99 Preparations E and F Same as Preparations A and B 3g 3gPreparations G and H.. Same as Preparations C and D g; 52 Examples 3 and4 Same as Examples 1 and 2 3g 33 Preparations .T and K N -oleyl citrlmieacid 3 32 Preparations L and M 1-(2-hydroxyethyl) 2-tallow imidazoline 2Examples 5 and 6 l-(zhydroxyethyl) Z-tallow imidazolinium N- 99 99 oleylcitrimate. do 100 100 Preparations N and 0..... Same as Preparations Jand K Egg? 9}} I: g2 g3 Preparations P and Q Same as Preparations L andM 2 PT j f gi fj z g? Examples 7 and 8 Same as Examples 5 and 6 $g Ef fgg; 88

1 PTB =Pounds per thousand barrels. 1 PTB is approximately 0.003 weightpercent. 9 A premium grade blended gasoline containing? cc.stetraethyllead per gallon. a A blend of distillate oils havingspecifications 111 the following ranges:

Distillation:

10% Recovery 348 to 410 F. 95% Recovery--." 465 F. or higher. EndPoint-.- 480 to 550 F. Gravity, API 41 to 43.

perature conditions. The corrosive materials become distributedthroughout both the hydrocarbon and aqueous phases and it becomesdesirable, if not necessary, to protect against corrosion of metal partsfrom both phases. The salts of this invention are useful in giving suchprotection from corrosion in both phases.

The results reported in the table demonstrate the superiority of thesalts (Examples 1-8) of this invention as corrosion inhibitors incomparison with each of two reactants (Preparations A-Q) which may beused to form the salts. In all cases, the salt gave at least aboutreduction in corrosion.

Although gasoline and heater oil were specifically used in the aboveexamples, the present corrosion inhibitors are useful in any normallyliquid hydrocarbon fuel. For example, the hydrocarbon fuel may be a jet,diesel or other internal combustion engine fuel, a burner fuel or otherheater or furnace fuel, or the like. More specifically, the fuel or fueloil may be a diesel fuel, a gasoline, a jet fuel, a heavy industrialresidual fuel (e.g., bunker C) a furnace oil, a heater oil fraction,kerosene, a gas oil, etc. The fuel may be cracked or virgin distillateor mixtures thereof. Residual oils are also useable. Advantageously thefuel may boil in the range of about 200 to 750 F., e.g., a distillatefuel oil out boiling in the 350 to 650 F. range.

Other fuels useable will be readily recognized by those skilled in theart from the above descriptions.

It is evident that I have provided new anduseful imidazoliniumcitrimates and inhibited hydrocarbon fuels containing the same.

I claim:

1. A fuel composition comprising a major amount of a liquid hydrocarbonfuel and an amount sufiicient to inhibit rust and corrosion of a salt of1,2-disubstituted imidazoline and citrim-ic acid, said saltcorresponding to the 2. The fuel composition of claim 1 wherein saidamount of said salt is from 0.00005 to 1.0 Weight percent.

3. The fuel composition of claim 1 wherein said hydrocarbon fuel boilsin the gasoline distillation range.

4. An addition agent concentrate comprising from 10 to 75% by Weight ofthe salt of claim 1 and a suitable solvent therefor, said concentratebeing capable of dilution With a liquid hydrocarbon fuel to a saltcontent of from 0.00005 to 1.0 weight percent.

References Cited by the Examiner UNITED STATES PATENTS 2,773,879 12/1956Sterlin 4463 2,907,646 10/ 1959 OKelly et a1 44-63 2,919,979 1/1960Martin et al. 44-63 3,060,007 10/ 1962 Freedman 4463 DANIEL E. WYMAN,Primary Examiner.

Y. M. HARRIS, Assistant Examiner.

1. A FUEL COMPOSITION COMPRISING A MAJOR AMOUNT OF A LIQID HYDROCARBONFUEL AND AN AMOUNT SUFFICIENT TO INHIBIT RUST AND CORROSION OF A SALT OF1,2-DISUBSTITUTED IMIDAZOLINE AND CITRIMIC ACID, SAID SALT CORRESPONDINGTO THE STRUCTURAL FORMULA: